The invention relates to a method for manufacturing a shoe in which parts of an upper protrude into a hollow mold that serves to produce a shoe bottom and are held against a sidewall of the hollow mold by fixation means, such that the parts of the upper are connected with the shoe bottom after a cork particle-containing or similar material has been poured into the mold and the upper form has been set in place. The invention further relates to a shoe manufactured according this method.
A method of the above-described type is disclosed in German Laid-Open Publication DE 195 11 942 A1. The hollow mold to be used in this method has pockets and holding frames which serve as fixation means for the lateral parts of an upper and hold these lateral parts until the shoe bottom material has been placed into the mold and has bonded to the lateral parts. Because of the pockets and the holding frame the design of the hollow mold is very complex and therefore costly. A further drawback is that the shape of the pockets and the holding frame determine the shape of the upper, so that the hollow mold cannot be used for differently styled shoes. If the shoe bottom material used for the shoe manufactured according to this method is not sufficiently abrasion resistant, then an outer sole is bonded to the underside of the shoe bottom. This bonding process is labor intensive, however, and often undesirable because solvents are released, and the bonding layer strongly reduces the vapor permeability of the shoe bottom.
Manufacturing a shoe bottom in a closed hollow mold from a cork particle-containing material—particularly a cork-latex mixture—involves the problem that the compression of the material, which occurs when the hollow mold is heated, causes a partial separation of the suspension. To prevent this, the material must be able to escape from the hollow mold in a controlled fashion, but this involves the risk of soiling either the material of the shoe's upper or the cover sole. Furthermore, the leakage of the material makes it necessary to clean the leakage areas as thoroughly as possible, which requires additional process steps. The aforementioned Laid-Open Publication DE 195 11 942 A1 does not address the separation problem of the cork-latex mixture or the avoidance of compression of the material within the closed mold.
The object of the invention is to develop a method of the initially described type, which uses a particularly simple hollow mold and prevents the separation of the shoe bottom material by avoiding compression within the hollow mold without the risk of soiling parts of the shoe. A further object of the invention is to create a shoe that can be manufactured according to this method.
According to the invention, the first object is attained by using an upper form configured to leave a clearance between its edge and the sidewall of the hollow mold and by inserting a cone plate into this clearance after the upper form has been placed, such that the cone plate tapers toward the interior of the hollow mold and on the inside presses the upper against the sidewall of the hollow mold while leaving a narrow gap to the edge of the upper form.
The use of the cone plate achieves two ends. On the one hand, the area of the upper is reliably pressed against the side wall, so that there is no risk of shoe bottom material rising between the exterior of the upper and the sidewall of the hollow mold. On the other hand, the cone plate leaves a gap between the upper form and the cone plate through which the material can escape in a controlled manner without soiling the shoe. Furthermore, the leaked material can be easily removed from the finished shoe.
In a further particularly advantageous refinement of the method according to the invention, after the areas of the upper have been inserted into the mold and the material forming the shoe bottom has been filled in, a cover sole is placed onto this material and the upper form is inserted, such that when the cone plate is inserted, the cover sole fits against the upper form with an edge folded up toward the exterior of the upper form. As a result, the upper is pressed against the top edge of the sidewall of the hollow mold and the narrow gap is created between the cone plate and the turned-up edge of the cover sole. After the shoe has been removed from the hollow mold, the turned-up edge of the cover sole is neatly trimmed.
This procedure makes it possible to completely exclude any soiling of the upper and the cover sole by leaking sole material. Moreover, the leaked material can be easily and neatly trimmed together with the edge of the cover sole.
In a further refinement of the method according to the invention, the parts of the upper that protrude into the hollow mold are fixed not only by the cone plate at the top edge of the sidewalls of the hollow mold but are held against the sidewalls also at their lower end. An outer sole, placed into the hollow mold before the material forming the shoe bottom is filled in, holds the lower ends of the parts of the upper that are protruding into the hollow mold against the sidewall of the hollow mold by fixation means provided on the outer sole.
It is particularly advantageous to use a cork-latex mixture as the material for the shoe bottom.
The second of the above-described objects, namely the creation of a shoe with an outer sole covering a shoe bottom and an upper connected with the shoe bottom, is attained according to the invention by the upper extending to the outer sole and the outer sole having upwardly projecting fixation means on the inside of the upper. In the finished shoe the material of the shoe bottom covers the fixation means. In such a shoe, the fixation means required for the simplified production of the shoe are not visible and do not affect the wearing comfort of the shoe. The fixation means can nevertheless be very simple in their design and enable a simple insertion of the upper when the shoe is being manufactured.
In a particularly simple design, the fixation means are formed by upwardly projecting nubs that extend parallel to the edge of the outer sole. Such nubs fix the upper and at the same time readily allow the shoe bottom material to flow up to and against the material of the upper.